A well-known method for the production of phenol and acetone is oxidation of cumene with atmospheric oxygen, followed by the acid-catalytic decomposition of cumene hydroperoxide. This method permits both end products to be produced with high yield (see, for example, Kruzhalov B. D., Golovanenko B. N., Combined Production of Phenol and Acetone, Moscow, Goskhimizdat, 1964, or Kirk-Othmer Encyclopedia of Industrial Chemistry).
Methods are known for producing phenol and acetone in which, to reduce the yield of phenol tar, cumene oxidation products containing cumene hydroperoxide (CHP), cumene, and dimethylphenylcarbinol (DMPC) are cleaved in the presence of sulfuric acid. In a first stage, at a temperature of 55 to 80° C., most of the CHP (75 to 99%) is decomposed and dicumyl peroxide (DCP) is produced from DMPC and CHP. In a second stage, acetone is added at a temperature from 80 to 146° C. to the obtained reaction mixture containing phenol, acetone, dimethylphenylcarbinol (DMPC) and dicumyl peroxide (DCP). The addition is made in an amount of 1.5 to 1.8 times the original concentration of acetone. Water is also added in the process. In some cases the acid is partially neutralized with ammonia before the second separation stage in order to ensure optimal acidity of the catalyst. After breakdown of DCP formed in the first stage, decomposition of the remaining CHP and dehydration of the remaining DMPC occur at a temperature from 80 to 146° C.
These methods significantly reduce the amount of formed byproducts in comparison with decomposition in one stage (the yield of tar is 25 kg/t of phenol), whereas the amount of formed by-product (hydroxyacetone) remains at a high level (and sometimes increases). These and other shortcomings of the prior art are addressed by the present disclosure.